The goal of this research program is to develop a new approach for preventing and treating chemotherapy induced alopecia. This is being accomplished by evaluating the safety and efficacy of topically administering a parathyroid hormone related peptide (PTHrP) receptor agonist or antagonist to mice that received cyclophosphamide. Results suggest that the topical application of a PTHrP antagonist before and after cyclophosphamide treatment markedly reduce the dystrophic changes induced by cyclophosphamide on the hair follicle. The topical application of a PTHrP receptor agonist before and after cyclophosphamide therapy enhanced cyclophosphamide effect on inducing alopecia. An evaluation of the long term effect of topically applying a PTHrP receptor antagonist or agonist before and after cyclophosphamide therapy resulted in a more rapid regrowth of the hair on mice that received cyclophosphamide compared to the group of mice that received cyclophosphamide and the daily topical application of a placebo cream. PROPOSED COMMERCIAL APPLICATION: The results from this study offer the potential for the commercialization of a PTHrP receptor antagonist for the mitigation of hair loss in patients who are treated with chemotherapy. In addition, topical PTHrP receptor agonist and antagonist can be commercially developed to accelerate hair regrowth in patients who receive chemotherapy and have significant hair loss.